The present invention concerns a local mobile access network equipped with means for managing the resources in said network.
A local mobile access network RLAM to which the present invention can be applied is shown in FIG. 1. This local network consists of a number of radio terminals BR each connected, via a multiplex marked P4, to a number of concentrators CTR (three here). Each concentrator CTR is connected, by a multiplex marked P3, to a virtual circuit switch VCX which, in turn, is connected, by a multiplex marked P0, to a general network RG. Each element of the local network RLAM uses the technology known under the name ATM (Asynchronous Transfer Mode).
It will be noted that the multiplexes marked P4, P3 and P0 are bidirectional multiplexes.
With this type of access network, communications are managed in the switch circuit VCX. They can be local when they are established between mobile units linked to the local network RLAM in question. They can be outgoing when they are established between mobile units linked to the network RLAM in question and to any terminal equipment of the general network RG.
In the present description, we shall say that a mobile unit is linked to a local network RLAM when it passes under the radio coverage of one of the terminals BR connected to this network. By way of example, the coverage of such a network could be of an average agglomeration. Always by way of example, several networks of this type can be juxtaposed to increase the geographic area covered. Thus, a large-scale regional or national network should amalgamate a more or less significant number of local access networks RLAM.
It is understood that the present invention is not limited to an access network like the one shown in FIG. 1. It could be applied to a network having a more complex architecture because it consists of a number of more significant concentration and switching stages.
In the present description, we shall call the concentration stage and the virtual circuit switch(es) concentrators CTR of the network.
Moreover, in this description, the local networks will be considered to be both dedicated and shared. In both cases, the architectures are very similar, the only differences being in the fact that the second has terminal installations other than mobile.
A mobile unit which is already connected and which is thus linked to one of the terminals BR can, when it is shifted, find itself covered by a second or several other radio terminals BR. Thus, it can be momentarily linked to several terminals BR. It can then be said that this mobile unit is in a xe2x80x9chand-overxe2x80x9d phase. In this phase, the information which it transmits is received simultaneously by the terminals BR to which it is linked and it, in turn, receives information coming simultaneously from said terminals BR.
The local mobile networks RLAM generally comprise macrodiversity server equipment OPM whose role is described in greater detail below. Equipment of this type is shown in FIG. 1 which is connected to the switch VCX by two multiplexes marked P1 and P2.
It will be noted that, contrary to the multiplexes P4, P3 and P0, the multiplexes P1 and P2 are unidirectional multiplexes. This is shown by the arrows for the unidirectional multiplexes which are, moreover, absent for the bidirectional multiplexes.
FIG. 2a shows, in the network RLAM shown in FIG. 1, the ascending direction (mobile to network) of a communication example during a hand-over phase. The mobile unit MB is linked to three terminals BR1, BR2 and BR3, two of which BR1 and BR2 are connected to the same concentrator CTR1 and the third BR3 to concentrator CTR2. In this ascending direction, the information transmitted by the mobile unit MB is then recopied three times in the local network RLAM. The flow is then multiplied by two on the multiplex P3 between concentrator CTR1 and switch VCX and it is multiplied by 3 on multiplex P2.
Generally, in the ascending direction, the mobile unit MB is linked to the local network RLAM as many times as there are terminals BR monitoring the mobile unit and the flow consumed in the network is increased to the different points of concentration.
From a general point of view, the function of the macrodiversity server equipment OPM is to filter the flow (here three) coming from the same mobile unit MB and present on the multiplex P2 and to retain only one, generally the one which has the best quality, that it delivers on the multiplex P1, in order to not unnecessarily xe2x80x9cencumberxe2x80x9d the network RLAM. This operation is generally called a xe2x80x9cmacrodiversityxe2x80x9d operation.
It is specified that, when a mobile unit is covered by several terminals, the radio links are generally of a very unequal quality.
In FIG. 2a, on multiplex P1, the filtered flow is unique. In this FIG. 2a, an outgoing communication is considered even though the flow present on multiplex P1 is then found on multiplex P0. It will be noted that, in the case of a local communication, the flow on multiplex P1 is shunted, by switch VCX, toward the concentrator CTR with which the addressee is connected.
FIG. 2b shows the descending direction (network to mobile unit) of the information. The switch VCX transmits the signal to the two concentrators CTR1 and CTR2. The concentrator CTR1 transmits to the two terminals BR1 and BR2 while concentrator CTR2 transmits to terminal BR3. The same signal is then received three times by the mobile unit MB. More generally, the processing of the macrodiversity is carried out in the mobile unit MB itself and does not pose any specific problems at the level of the network RLAM. It will be noted that the descending connection is of the point-to-multipoint type.
In an ATM network, whatever it may be, a virtual connection is established by marking a path and requires the reservation of a passband on this path in accordance with the requirements expressed and required, by the caller at the time the connection is established, for the service performed on this path.
Although in the case of telephony, the resources consumed are limited to a few ten Kbits/s for a communication, in the case of videophony, on the other hand, the resources consumed attain several hundred Kbits/s, or even more.
Conventionally, an ATM multiplex supports a passband higher than 100 Mbits/s. Thus, at least at the level of the local part of the network, the number of connections for telephony simultaneously established will never permit this limit to be attained. That is not the case for videophony.
Henceforth, two factors should be taken into account which risk significantly increasing the flow rate and which require implementing methods which enable maximum management of the flow rates. On the one hand, the perspective of a future deployment on the radiotelephony networks for new services is inescapable. On the other hand, the macrodiversity which is a feature suitable for this type of network results in an increase of the flow rates during hand-over phases.
Therefore, the object of the invention is to propose a mobile access network which makes it possible to take into account the increase in the flow rate which results from hand-over phases.
To this end, a mobile access network of the type which generally comprises a number of radio terminals linked via concentration stages, to another concentration stage composed of a virtual circuit switch, is characterized therein that at least said concentration stage comprised of said virtual circuit switch is equipped with macrodiversity management equipment and therein that each concentration stage downstream from the or a concentration stage equipped with a macrodiversity management equipment is furnished with a management device for the flow rates provided to manage the resources on the multiplex which is located directly above the concentration stage which it supplies.
In the present description, it is considered that the links are called ascending when they originate with a radio terminal and terminate at the main virtual circuit switch of the network, while they are called descending in the other direction. Consequently, a concentration stage is downstream from a second one when it is situated between said second stage and a radio terminal and it is ascending from a second one when it is situated between said second stage and said virtual circuit switch of the network.
According to another feature of the invention, each management device controls the flow rate on the multiplex which is found directly above the concentration stage which it equips and, when said multiplex cannot support the required flow rate for a new connection of a hand-over phase communication, instructs said network not to establish said connection.
According to another feature of the invention, the receiving terminal under the coverage of which a mobile unit already connected comes to pass is provided for transmitting a connection request message which is transmitted to the management device which equips the concentration stage further downstream and said device, on receiving said message and when the multiplex which it controls can support the flow rate requested for said new connection, retransmits said message to the management device of the concentration stage directly above, this process being continued up to the management device of the concentration stage (CTR, VCX) furnished with macrodiversity management equipment and, when the multiplex which controls one of said management devices in question, cannot support the flow rate requested for said connection, said management device in question requests said network not to establish said connection.
According to another feature of the invention, the management device of the concentration stage which is equipped with macrodiversity server equipment, when the multiplex which it controls can support the flow rate requested for said new connection, transmits to the concentration stages downstream therefrom in direction of said receiving terminal, a new message for marking said new connection in said stages.
According to another feature of the invention, said message also contains a request for allocation of a flow rate.
According to another feature of the invention, the management device which equips the concentration stage and is also equipped with macrodiversity management equipment controls the flow rates on the multiplex which links said concentration stage to said macrodiversity management equipment.
According to another feature of the invention, each resource management device comprises a memory in which the value of the flow rate supported by the monitored multiplex is stored and updated.
According to another feature of the invention, the equipment for processing calls of said network participates in said updating of the memory of each resource management device.
According to another feature of the invention, each resource management device only monitors the flow rate of the multiplex in question in ascending direction.